Communicating between individuals has generally required traditional verbal communication devices and systems such as phones, and the like, that are not acceptable and/or practical in certain environments. For example, getting situation-relevant information to dismounted soldiers is key to achieving victory on the battlefield. Indeed, the reliable communication of information regarding the location and severity of threats is part of the goal of the Land Warrior System currently in development by the US Army.
A challenge in accomplishing this task is designing systems for providing information in diametrically opposed scenarios. The first is full-fledged combat, a circumstance replete with a barrage of noise and context-irrelevant signals. The second is that of night covert operations, scenarios in which maintaining silence and the cover of darkness are mandatory for success. Despite the apparent disparities between these scenarios, the information most relevant to soldiers remains the same: locations of threats as well as assets. Due to the critical nature of threat information, it is an absolute necessity to present it through omnipresent communication channels.
Current methods of communication do NOT effectively and covertly alert soldiers to the presence of threats while simultaneously cueing their locations. Due to the constraints of these environments, solutions cannot rely on verbal or visually based systems.
Vision and visual cues are not generally available and always practical in military battle environments. Visual displays of alerts and alarms generally “work” only when the operator looks in their general direction. Also, use of light-based systems during night operations negates the advantage gained through the use of night vision equipment.
Speech and verbal cues are not always available or practical in covert military operations. Verbal communication requires transmission that may be intercepted by unfriendly individuals within range of the communication. The interception would alert the unfriendly individuals of the military personal position which negates the advantages gained by covert operations.
A desired system must appeal to one of two remaining omnipresent sensory systems through which one can derive directional information by audition or touch. Over the years attempts have been made at providing 3-dimensional spatial information both aurally and tactually, but they have achieved limited success.
Users of binaural 3-dimensional audio systems frequently experience front-back reversals, wherein sounds from behind the user are perceived as being in front. In addition, the ability of the auditory system to discriminate among sounds located at different elevations is poor. People often must tilt their heads to localize sounds, especially when their sources are at elevations greater than −13 to +20 degrees from the horizon (Buser & Imbert, 1992), although our ability to resolve sound locations in the horizontal plane is of greater accuracy (McKinley & Ericson, 1997).
As with 3-dimensional audio systems, there have been some attempts for using tactile-based systems. An example of a known system is the Tactile Situation Awareness System (TSAS), a wearable tactile display intended to provide spatial orientation cues (Rupert, 2000). To aid in the development of TSAS, Cholewiak, Collins, and Brill (2001) conducted a study to evaluate the spatial resolution for vibration applied to the torso. They used wearable displays consisting of eight small vibrating devices called tactors, spaced equidistant across the abdomen and arranged to represent the points of the compass (i.e., navel=“north,” spine=“south”). The results showed that participants were very accurate in localizing stimuli applied to the naval and spine (nearly 100%), but accuracy was lower for localizing stimuli on the sides.
The inventors have found that a six-tactor array improved accuracy over that of the eight-tactor array (97% versus 92%, respectively; Cholewiak, Brill, & Schwab, in press). It was also found that the ambiguities regarding localization of vibratory stimuli on the sides could be resolved by modulating vibration frequency. By providing unique sensations in the “east” and “west” positions, significant improvements in localization accuracy (to approximately 95%) were produced, even with an eight-tactor display. Although tactile displays might be somewhat restricted in terms of the number of loci that can be accurately resolved in the horizontal plane, the sense of touch boasts a significant advantage over audition in regards to accurately perceiving stimuli in the vertical plane and in circumventing the problem of front-back reversals.
Use of tactile communication systems might have additional advantages over auditory displays, particularly pertaining to the combat scenario. The prior art suggests that tactile communication might avoid potential conflicts in sharing cognitive resources, a problem that could arise with auditory alarms (Wickens, 1984). Although Wickens' model of attention (1984) lacks an allocation of resources to the sense of touch, there is little ambiguity regarding the effects of resource sharing between tasks appealing to the same sensory modality.
It is unlikely that soldiers will be able to send and receive verbal communications while simultaneously attending to an auditory alarm amidst the noise and stress of combat. Considering the likelihood of task saturation in the auditory channel, a tactile system holds promise not only because of its inherent qualities, but also because it should not interfere with vision or audition (Parkes & Coleman, 1990; Wickens, 1984; Wickens, Sandry, & Vidulich, 1983). Therefore, it is much more reasonable to suspect that soldiers will be able to receive and attend to tactile information (versus auditory information) due to the lack of competition for mental resources and in the relative absence of cross-sensory masking. As information received tactually should not compete with other signals for mental resources, its impact on mental workload is likely minimal.
In environments such as during battles and the like, human senses such as hearing, vision and smell can be overpowered and are impaired. For example, troops may not be able to hear verbal commands and verbal communications when explosions and artillery fire is underway. Tactile sensors can be useful for providing some information but still fail by themselves to effectively communicate desired communications between parties. The inventors are aware of several patents and published patent applications that use some types of tactile stimulation.
See for example, U.S. Publication 2005/0162258 to King which provides a tactile stimulation in response to an alarm condition; U.S. Pat. No. 6,930,590 to Ling, et al. describes a system for delivering tactile stimuli to the skin surface using an array of electrodes directly connected with a pc board and may be used as a wearable article; and U.S. Pat. No. 6,326,901 to Gonzales which includes an array of stimulators for transmitting alphanumeric data.
A number of the referenced applications and patents are directed toward medical devices for monitoring user vital signs or delivering medical treatment to the user. These references include the U.S. Pat. No. 6,561,987 to Pail (respiratory); U.S. Pat. No. 6,341,229 to Akiva (ECG testing); U.S. Pat. No. 5,181,902 to Erickson (pulsed electromagnetic field (PEMF) therapy); U.S. Pat. No. 4,889,131 to Salem (cardiac and respiratory); and U.S. Pat. No. 4,494,553 to Sciarra (cardiac and respiratory) patents. U.S. Pat. No. 4,736,196 to McMahon is a monitoring system that can be used to track the location of a wearer.
U.S. Publication 2005/0132290 to Buchner, et al. discloses the closest prior art of a method and apparatus for transmitting information to a user's body using standard codes and an actuator that can be used to transmit tactile, vibrational, heat, pressure or electric pulses to transmit information using the skin as an interface to the user wherein the apparatus is contained in a wearable garment or accessory. The device described in Buchner is complex and includes a display for viewing an emotional state using symbols or moving images and can be used to listen to recorded music. The biometrics are processed by an expression interpreter to determine emotions.
Other art made of record includes U.S. Published Patent Applications: 2005/0173231 and 2005/0152325 to Gonzales; 2005/0073439 to Perricone; 2003/0109988 to Geissler; and 2002/0145522 to Pembroke. See also U.S. Pat. No. 6,856,578 to Magine; U.S. Pat. No. 6,771,224 to Apostolos; U.S. Pat. No. 6,392,540 to Brown; U.S. Pat. No. 6,326,901 to Gonzales; U.S. Pat. No. 6,320,496 to Sokoler; U.S. Pat. No. 5,719,561 to Gonzales; U.S. Pat. No. 4,008,456 to Ewart; U.S. Pat. No. 3,736,551 to Hirsch; and U.S. Pat. No. 3,108,268 to Uttal.
However, none of the above references disclose an apparatus or method for communicating qualitative and quantitative tactile cues while also monitoring user vital signs that is usable for covert operation without broadcasting signals that may be intercepted by unfriendly individuals within range.